1. Field of the Invention
The present invention relates to an optical fiber connector mounted to an end part of an optical fiber.
2. Related Art
Conventionally, there has been widely used an optical fiber connector that optically connects a first optical fiber with a second optical fiber (refer to, for example, Japanese Unexamined Patent Publication No. 2005-091379).
The optical fiber includes a fiber wire and a jacket that surrounds the fiber wire, and has on a distal end side thereof a cladding part where the fiber wire is exposed.
The optical fiber connector is attached to the distal end side of the optical fiber.
More specifically, the optical fiber connector includes a housing that is detachably coupled to an adapter, a rigid ferrule that is accommodated in the housing in a movable manner along an axial line direction with a distal end thereof being extended outwards from the housing, the ferrule being formed on a proximal end side thereof with a first axial hole having a first inner diameter which is larger than the outer diameter of the jacket and on the distal end side with a second axial hole being communicated to a distal end of the first axial hole and having a second inner diameter which is smaller than the first inner diameter and is larger than the outer diameter of the fiber wire, and a bias member that biases the ferrule toward the distal end side within the housing.
The optical fiber connector is fixed to the optical fiber with use of an adhesive agent filled in the first axial hole in a state where the fiber wire of the cladding part is inserted into the second axial hole and a portion (hereinafter, referred to as a fixed region) of the optical fiber which is surrounded by the jacket and which is adjacent to a proximal end of the cladding part is inserted into the first axial hole.
Although the optical fiber connector is useful in facilitating optical connection between the first optical fiber and the second optical fiber in cooperation with the adapter, it has, on the other hand, room to improve in terms of adhesion between the optical fiber and the ferrule.
Specifically, the first axial hole functions as a guide that leads the fiber wire of the cladding part so as to be inserted into the second axial hole, as well as functions as an adhesive agent filled region that receives the adhesive agent with the fixed region being inserted therein.
In a case where the inner diameter of the first axial hole is set as approximately equal as possible to the outer diameter of the jacket while allowing the fixed region to be inserted into the first axial hole, the first axial hole can effectively function as the guide. However, at the same time, it becomes difficult to evenly fill the adhesive agent around the fixed region and to fill the adhesive agent into the distal end of the first axial hole. Thus, in some cases, the optical fiber and the ferrule may not be solidly fixed with each other.
To the contrary, in a case where the inner diameter of the first axial hole is made extremely larger than the outer diameter of the jacket, the adhesive agent can be easily filled in. However, at the same time, decreased is the function of the first axial hole as the guide. Furthermore, if the inner diameter of the first axial hole is made too large, the axial position of the fixed region may be displaced with respect to the axial position of the second axial hole when the adhesive agent is being filled in or being solidified. When the fixed region is axially displaced, the boundary between the cladding part and the fixed region is applied with a stress in a direction different from the axial direction of the optical fiber. In some cases, the fiber wire may be deformed by such a stress.